In recent years, a variety of power devices driven by the electronic power are continuously being created because the concept of the environmental protection is increased, for example, the development of the electronic vehicle industry. General speaking, the power source of the power device driven by the electronic power is the battery pack. Taking the electronic vehicle for an example, the cost of the battery pack used by the electronic vehicle is 750˜1000 NT$/kwh (10 kw per hour), but the cell battery cycle life only has 800˜1000 times. Moreover, taking an electronic postal vehicle, which uses the battery pack with 12 kwh has the endurance of 80 kilometer for an example, it supposes the cost of the electronic postal vehicle is same as other gasoline cars, and further calculates the amortization cost of the battery pack and the charging cost (at least NT$ 5/km) of the electronic postal vehicle. As a result, the every mileage driving cost of the electronic postal vehicle is more than the gasoline cars twofold price, resulting in the amortization cost of the electronic postal vehicle is higher than the gasoline car. Additionally, the electronic postal vehicle must exchange the battery pack when it drives over 8 kilometers. Therese disadvantages hinder the market share of the electronic vehicle.
About the “long-lived cell battery”, only Toshiba (SCiB) and Mitsubishi Electric (composite electrical storage devices) generate the cell battery cycle life having over 2000 times, wherein the composite electrical storage device having lithium cell serial connected with the ultracapacitor (14 Wh). However, the cost and the output of both still can not satisfy the demand.
The U.S. Pat. No. 7,489,048 with the title of “Energy storage system for electronic or hybrid vehicle” discloses a power storage system with two battery packs, a adjustable circuit serial/parallel connected the two battery packs and a external passive storage device serial connected with the power storage system via a interface. The control method of the patent is that when the motor is low-speed (below 50% rated), the two battery packs are parallel connected; when the motor is high-speed (upper 50% rated), the two battery packs are serial connected. Because this patent must mount two battery packs, the configuration of it is large, complicated and high-cost. Moreover, the system in the patent must perform two-steps power control according to the speed of the motor, and it can not adjust adaptive mode according to different states.
Regarding to the problems in power control of the battery pack mentioned above, it must spend a long-running time and high-cost to develop the long-life battery at the material. Therefore, it is important topic that how to generate a new way that is different with the new material development, and uses power management and control method to advance the cell battery cycle life, and effectively discharge and charge, and lower the amortization cost of the battery (at least not higher than the general gasoline car).